Reset effect chain volume whenever the volume controller effect stopped

so the correct volume can be apply to the new volume controller

Bug: 347866898
Flag: EXEMPT bugfix
Test: repro steps in b/34786689
Test: atest CtsMediaAudioTestCases
Change-Id: I38187906f74c7cabc564d1aa01426257a0d90ba6
(cherry picked from commit f62fbceee74181ff59727d1bc708bcf41cb95667)
Merged-In: I38187906f74c7cabc564d1aa01426257a0d90ba6
diff --git a/services/audioflinger/Effects.cpp b/services/audioflinger/Effects.cpp
index d9a9a9c..e85329d 100644
--- a/services/audioflinger/Effects.cpp
+++ b/services/audioflinger/Effects.cpp
@@ -617,10 +617,11 @@
 
 }
 
+// return true if any effect started or stopped
 bool EffectModule::updateState_l() {
     audio_utils::lock_guard _l(mutex());
 
-    bool started = false;
+    bool startedOrStopped = false;
     switch (mState) {
     case RESTART:
         reset_l();
@@ -635,7 +636,7 @@
         }
         if (start_ll() == NO_ERROR) {
             mState = ACTIVE;
-            started = true;
+            startedOrStopped = true;
         } else {
             mState = IDLE;
         }
@@ -655,6 +656,7 @@
         // turn off sequence.
         if (--mDisableWaitCnt == 0) {
             reset_l();
+            startedOrStopped = true;
             mState = IDLE;
         }
         break;
@@ -669,7 +671,7 @@
         break;
     }
 
-    return started;
+    return startedOrStopped;
 }
 
 void EffectModule::process()
@@ -2305,6 +2307,9 @@
     }
     bool doResetVolume = false;
     for (size_t i = 0; i < size; i++) {
+        // reset volume when any effect just started or stopped.
+        // resetVolume_l will check if the volume controller effect in the chain needs update and
+        // apply the correct volume
         doResetVolume = mEffects[i]->updateState_l() || doResetVolume;
     }
     if (doResetVolume) {
@@ -2658,6 +2663,9 @@
                                        true /* effect chain volume controller */);
         mNewLeftVolume = newLeft;
         mNewRightVolume = newRight;
+        ALOGD("%s sessionId %d volume controller effect %s set (%d, %d), ret (%d, %d)", __func__,
+              mSessionId, mEffects[ctrlIdx]->desc().name, mLeftVolume, mRightVolume, newLeft,
+              newRight);
     }
     // then indicate volume to all other effects in chain.
     // Pass altered volume to effects before volume controller